With estimates of the incidence of prediabetes in the USA at over 84 million people, prediabetes is an epidemic by any definition. It is also one of the leading causes of peripheral neuropathy with some 18% of prediabetics–15 million people in the USA–estimated to be suffering from peripheral neuropathy.
Because diabetic and prediabetic peripheral neuropathies are both the result of glucose dysregulation, it is not surprising that they present similarly. The neuropathy of prediabetes is a small fiber neuropathy characterized by burning, tingling, numbness, and shooting pains, starting in the toes and ascending over time up the feet and legs in a length dependent, symmetrical fashion.
The diagnosis of prediabetes can be determined by running a HbA1c and/or an oral glucose tolerance test. Small fiber neuropathy can be diagnosed by performing an intraepidermal nerve fiber density biopsy. As always, a detailed history and physical should be performed.
Prediabetic peripheral neuropathy should be treated in a similar manner as diabetic peripheral neuropathy. Lifestyle changes including exercise and diet modifications should be strongly suggested to prediabetics. Consider recommending a diabetic counselor. Appropriate shoes and orthoses should be recommended to protect feet with decreased sensitivity. Physical therapy should be considered in order to reduce fall risk. Benfotiamine and vitamin B12, when used properly, have proven to be very helpful in reducing symptomatology. Other B vitamins, alpha lipoic acid, evening primrose oil, and other nutrients may prove helpful. In more severe cases, the use of analgesics, anticonvulsants and antidepressants may be necessary.